Safety device for electric elevators.



N0. 726,370. PATENTED APR. 28, 1903. A. SUNDH.

SAFETY DEVICE FOR ELECTRIC ELEVATORS.

APPLICATION FILED SEPT. 12. 1902.

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L' 44 WITNESSES: INVENTOR Q W LygS I Tn: Noam PEFERS c0, FHOTU-UTHO, WASHINGTON, mv c PATENTED APR. 28., 1903.

A. SUNDH. SAFETY DEVICE FOR BLEGTRIG ELEVATORS.

APPLICATION FILED SEPT. 12, 1902.

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WITNESSES:

' UNITED STATES PATENT OFFICE.

AUGUST SUNDH, OF YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF EAST ORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SAFETY DEVICEFOR ELECTRIC ELEVATORS.

SPECIFICATION forming part of Letters Patent N 0. 726,370, dated April 28, 1903.

Application filed September 12 1902. Serial No. 123,149. (No model.)

To It whom it may concern:

Be it known that 1, AUGUST SUNDH, acitizen of the United States, and a resident of the city of Yonkers, in the county of Westchester and State of New York, have invented new and useful Improvements in Safety Devices for Electric Elevators, of which the following is a specification. In electric elevators which are operated or to controlled electrically it sometimes happens that the main fuse through which the current passes to the armature of the motor is blown while the motor is running and that the rotation of the armature generates sufficient electromotive force to supply the auxiliary circuits with current enough to keep them operative and to hold off the brake, and this has been the cause of many serious accidents. This same result follows if the main 2o switchis opened under similar circumstances. To illustrate how this may happen, suppose the car is coming down at maximum speed with an extra heavy load, some one standing near the main switch thinks the car is running away and pulls open the switch to stop it. This would not stop it, but would have the opposite efiect, as the current generated by the armature would keep the brake released, and in some systems the opening of 0 the main switch would take the control of the elevator out of the power of the operator in the car, with disastrous results.

The object of my invention is to provide a simple and eflicient safety device to prevent 5' accidents of this nature.

Referring to the drawings, Figure 1 represents an electric elevator with my invention attached. Fig. 2 shows in perspective my safety device with its cover open. Fig.3 is a side elevation of the same in section.

Similar figures of reference indicate corresponding parts in the several figures.

Referring now to Fig. 1, 10 represents a well-known form of electric hoistingmachine, of which 11 is the motor, and 12 the brake-magnet, and it is shown connected by suitable cables to a car 20 and counterweight 21.

30 represents diagrammatically my safety device, which consists of the main fuses 31 I 32, Which are in the motor-circuit, and the auxiliary fuses 33 34, which are in the operating circuit. The latter fuses 33 34 are placed in proximity to the main fuses.

The auxiliary orv operating circuitis as follows: Starting from the main and going through the auxiliary fuse 33,it is led through the conductor 40 tothe car and connected to the upper blade of the carswitch 22. Whenever this switch is moved either to the right or left, this upper blade makes cont-act with the outer segment 23 and the circuit is completed through the conductor 41 and its branches 42 43 through the brake-magnet 12 and the solenoids 50 and 60 to the other main through the conductor 44 and its branches 45 46 47 and the auxiliary fuse 34. Thus moving the car-switch either to the right or left energizes the brake-magnet, which releases the brake, energizes the solenoid 60, which closes the armature-circuit at the contacts 61 62 through the armature starting resistance 51.

It also energizes the solenoid 50, which is arranged to cut out this starting resistance 51 by raising the contact-arm 52. The conductors 14 15 lead from the shunt-field of the motor 11 to the car-switch and are connected to the contacts 24 25. The upper blade of the carswitch is connected to the main by the condoctor 40 and the lower blade to the main by the conductor 44. When the car-switch is turned to the right,the l conductor 40 will be connected to the contact 25, and the current will pass through the conductor 15, through the field, and out through the cond uctor'14 to contact 24 of the car-switch,which will be in contact with the lower knife of the car-switch, and so connected to the main through conductor 44. By moving the carswitch to the left the current will flow the opposite way through the field-coils. In this way the field can be reversed by the operator in the car, who can thus start the motor rotating in one direction or the other by moving the car-switch to one side or the other, and 5 thus move the car up or down, as he desires.

In Fig. 2 1 have shown in perspective my invention embodied in a form of switch also invented by me and the subject of another application for Letters Patent, Serial No.

48,123. This switch consists, essentially, of two partsa base and a hinged cover 80, which contains the fuses and is so arranged that when the cover is closed the fuses are in their respective circuits; but when the cover is opened, as shown in Fig. 2, the fuses are removed from the circuits. Fig. 3 shows a sectional elevation of the switch in its closed position. A further description of this switch is not deemed necessary here, as it is fully disclosed in application Serial No. 48,123.

My present invention is not limited to the precise form of switch described and shown, as any form of switch which will open the auxiliary circuit independently and at the same time the main circuit is opened will answer the purpose.

The operation of my device is as follows: If for any cause the main fuses 31 32 are blown, the heat generated by them will melt the auxiliary fuses 33 3t, which are placed in proximity to them for this purpose. Thus when the main fuses are blown the operatingcircuit will be automatically broken, and as the brake-magnet 12 will no longer be energized the brake will be applied and will stop the machine Without any act of the operator. This will also def-Energize the solenoids 50 and 60 and the fields of the motor. Also if the main switch is opened at any time while the motor is running the auxiliary circuit will also be opened and the brake applied and the machine stopped in the same manner as above.

By using the form of switch shown in Figs. 2 and 3 I accomplish both of the above results by the use of one apparatus; but I do not wish to confine myself to this specific form of switch, as other well-known forms may be employed with or without the fuses being attached to the switch itself withoutdeparting from the spirit of my invention.

- While I have shown my invention applied to the circuits of an electric elevator, it is clear that the part which pertains to the melting of the fuses in one circuit by the heat caused by the melting of the fuses in another circuit is applicable to any other interdependent circuits, and as I believe this is new I do not wish to confine its use to the circuits of an electric elevator.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an electric elevator, the combination of a main circuit containing the motor-armature, an auxiliary circuit controlling a brake, switches for operating said circuits, a manually-operated switch to open both of said circuits together, substantially as described.

2. In an electric elevator, the combination of amain circuit containing the motor-arrnature, an operating-circuit controlling a brake, fuses in each circuit, those in the operatingcircuit arranged to be melted by the heat from those in the main circuit when the latter are blown, substantially as described.

3. In an electric elevator, the combination of a main circuit containing the motor-arma tnre, an operating-circuit controllinga brake, a manually-operated switch to open both of said circuits together, fuses in each circuit, those in the operating-circuit arranged to be melted by the heat from those in the main circuit when the latter are blown, substantially as described.

4. The combination of two interdependent circuits, fuses in each circuit so arranged that the fuses in the second circuit will be melted by the fusing of the fuses in the first circuit, substantially as described.

5. In an electric elevator, two interdependent circuits, fuses in each circuit, means for melting the fuses in the second circuit when the fuses in the first circuit are blown, substantially as described.

6. In an electric elevator, two interdependent circuits, switches and wiring connections in such circuits for the usual operation of the elevator, main switches for opening each'of said circuits, means for preventing the opening of one of said switches without also opening the other, substantially as described.

7. In an electric elevator, the combination of a main circuit and an auxiliary circuit, a switch containing independent fuses for each circuit, so arranged that both said circuits will be broken by the opening of the switch or the blowing of the main fuses, substantially as described.

8. In an electric elevator, the combination of a main circuit containingthe motor-armature, an auxiliary circuit controlling a brake, independent fuses in each circuit, means for applyin said brake whenever the fuses in the main circuit are blown, substantially as described.

9. In an electric elevator the combination of a main circuit containing the motor-armature, an auxiliary circuit controlling a brake, switches for operating said circuits, other switches for opening said circuits, means for preventing the opening of the main-circuit switch without opening the auxiliary-circuit switch, substantially as described.

10. In an electric elevator, the combination of a main circuit and an auxiliary operatingcircuit, means for independently breaking the auxiliary circuit by opening the main-circuit switch or the blowing of the main-circuit fuses, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

AUGUST SUN DH.

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